/Engine/Source/Runtime/Engine/Classes/GameFramework/CharacterMovementComponent.h
Attempts to better align navmesh walking characters with underlying geometry (sometimes navmesh can differ quite significantly from geometry). Updates CachedProjectedNavMeshHitResult, access this for more info about hits.
virtual FVector ProjectLocationFromNavMesh ( float DeltaSeconds, const FVector & CurrentFeetLocation, const FVector & TargetNavLocation, float UpOffset, float DownOffset )